Instrument for use in obtaining stroboscopic effects



Apri] 28, 1936. R` M. EATON 2,039,214

INSTRUMENT FOR USE IN OBTAINING STROBOSCOPIC EFFECTS Filed July 24, 1935 MMM MW Patented Apr. 28, 1936 INSTRUBIENT FOR USE IN OBTAINING STROBOSCOPIC EFFECTS Richard Maxwell Eaton, Niagara Falls, N. Y., as-

signor to Niagara Searchlight Co. Inc., Niagara Falls, N. Y.

Application July 24, 1935, Serial No. 32,932

3 Claims. (Cl. 176-124) 'I'his invention relates to improvements in -producing stroboscopic effects, such for example as are employed in instruments for use in determining synchronism of two members.

It has been found that in certain types of apparatus operating on the stroboscopic principle, the eects vary considerably. For example, in determining whether the ignition of an internal combustion engine is in properly timed relation to the rotation of the engine, a flashing light actuated by electric impulses supplied to a spark plug has been projected on a white mark on a fly wheel or other rotating part of an engine. With instruments of this type as heretofore used, diniculty has, however, been encountered due to the fact that the duration of the light was at times so long as to make the mark on the y wheel or rotating part visible over too great an arc of movement of the rotating part. Furthermore, the stroboscopic effect thus produced by the same instrument or apparatus varied on diierent engines.

The objects of this invention are to control the duration of the light in a stroboscopic device in such a manner as to render a mark on a revolving member visible only through a very small arc of its movement; also to control the duration of the light by controlling the current delivered to the light source; also to provide an instrument of this kind with an adjusting spark gap controlling the duration of light; also to improve methods and instruments of this kind in other respects hereinafter specified.

In the accompanying drawing:

Fig. 1 is a longitudinal central sectional elevation of an instrument for producing light flashes and provided with means embodying this invention for varying the duration of the flashes.

Fig. 2 is a fragmentary sectional elevation thereof on an enlarged scale, showing .the adjusting means associated with the instrument.

Fig. 3 is a transverse sectional "elevation on line 3 3, Fig. 1.

In instruments of this kind, the light source is generally in the form of a gas lled tube which is so constructed as to be illuminated by electrical impulses. A tube of this kind may be incorporated in any suitable type of apparatus or appliance and the construction illustrated bywayf of example, shows the tube applied to a portable:

tube extending into one end of the base II and being connected to suitable conductors I3 shown in broken lines in Fig. 1, which terminate in the other end of the base. This base is preferably secured within a cylinder I2 of insulating material arranged within the tubular body 5. The base II may be provided with laterally projecting pins or studs I5 arranged to enter into bayonet slots I 6 in the insulating cylinder I2 or the base may be otherwise removably'secured within the instrument. The inner end of the base portion II is provided with suitable terminals of the conductors I3, which engage with terminals I6 and I1 yieldingly pressed outwardly by means of springs I8 and I9 to insure adequate contact through which velectric current may be carried to the body portion II of the tube I0. The springs and movable contacts I6 and I 'I are suitably arranged in an insulating member or part 20 secured within the tubular body 5 of the instrument in any suitable manner, for example, by securing the insulatin member 20 to the insulating tube I2.

At the other end of the tubular body member 5, a ferrule or cap 24 is secured which has an inwardly extending flange engaging an insulating bushing 25 which, in the construction shown, in turn engages the end of the insulating cylinder I2. This bushing is provided with apertures through which suitable conductors 26 and 2l extend through which electric impulses may be transmitted to the gas-filled tube I0. The conductor 2B, for example, engages at its outer end with another movable contact point 28 also arranged in the insulating member 20 and urged into contact with the conductor 26 by means ofthe spring I8. All of the parts thus far described have heretofore been used in connection with instruments of this kind and of themselves do not constitute a part of this invention, being shown and described merely to illustrate by way of example, a device to which myinvention may be applied.

I have found that when instruments of this kind are used in connection with the ignition systems of Various types of internal combustionengines, the stroboscopic effects produced are not always suiciently clear to facilitate the' proper timing of an engine, since with some types of machines, the light colored mark formed on the y wheel or other part geared ,thereto is visible over such a large arc of movement of the rotatable part as to make it diicult or vimpossible to determine the correct timing of the engine. This is due to the fact that the light from the glow tube is too long in duration and this duration varies with different engines due to different electro-magnetic characteristics of the ignition system.

In accordance with my invention, I provide means whereby the duration of the light of the glow tube may be varied in such a manner that the mark on a revolving part of the engine will be visible only through a. very small arc of its movement. This I accomplish by providing means for varying the amount of current supplied to the glow tube. Any suitable or desired means for accomplishing this result may be used. In the particular construction illustrated, I provide an adjustable spark gap in the current leading to the glow tube, which may, for example, be effected by adjusting one or both of the conductors leading to the instrument toward and from fixed current conducting parts within the instrument. As shown in the drawing, I provide an adjustable spark gap between the end of the conductor 2l and a stationary conductor 30 secured in the insulating member 20 and in contact with the spring I9. For this purpose, I provide a sleeve 3| through which the cable 21 extends and to which the outer portion of the cable is secured. This sleeve 3| in turn may be adjustably mounted on the instrument in any suitable manner. In the construction shown, the insulating bushing 25 is provided with an aperture within which the sleeve 3| may be moved lengthwise against the frictional contact of the bushing. 25 with the sleeve 3|. If desired, the

bushing -25 may be provided with a hub or extension 32 which will afford a more extended frictional bearing for the sleeve 3|.

A variation of the spark gap or distance between the end of the cable 21 and the conductor 3 is effected by adjusting the sleeve 3| in and out with reference to the bushing 25. The correct position of the sleeve 3| produces a clear view of the mark on the revolving part, since the (lll mark on the revolving part may then be seen only in a small arc of movement of the revolving part.

This correct position can be readily determined by rst observing the mark on the revolving part. If this mark is in the form of a radial line made by chalk or light colored paint, then if the line appears in the form of a wide band, the spark gap is increased by adjusting the sleeve 3| and conductor 21 secured thereto outwardly. This adjustment is continued until the line is visible in the form of a narrow band. If this band is not in registration with the indicating mark on a stationary part near the revolving part, then the timing mechanism of the engine is adjusted to advance or retard the spark until the line or band is opposite the stationary indicating mark. If the line on the revolving part appears too faint or dim, the sleeve 3| is moved inwardly to reduce the spark gap.

It will, of course, be understood that any other means may be used for controlling the amount of current passing to the gas in the tube I0, the adjustable spark gap being merely illustrative of one embodiment of this invention.

I claim as my invention:

l. In an instrument for use in synchronizing two parts by means of effects obtained by electric light flashes, the combination of a body tube, a block of insulating material xed in said body tube, a gas-lled glow device mounted upon said body tube at one end of'said block, a pair of conductors mounted in and extending through said block and having electrical contact at one end thereof with the terminals of said glow device, a bushing of insulated material detachably secured at the other end of said body tube, a pair of insulated wires mounted upon said bushing with their ends extending into said body tube and effective to conduct electrical impulses to said conductors, and one of said wires being adjustable relatively to said bushing to form a variable spark gap between said wire and one of said conductors to vary the duration of light flashes produced by said glow device.

2. In an instrument for use in synchronizing two parts by means of eiects obtained by electric light flashes, the combination of a body tube, a block of insulating material fixed in said body tube, a gas-filled glow device mounted upon said body tube at one end of said block, a pair of conductors mounted in and extending through said block and having electrical contact at one end thereof with the terminals of said glow device, a bushing of insulated material engaging the other end of said body tube, a cap detachably connected to said body tube and engaging said bushing for releasably securing it upon said body tube, a pair of insulated electric wires having their ends extending through holes in said bushing into said body tube and one of which is in relatively xed relation to said bushing and engages one of said conductors and the other of said wires being movable endwise and being frictionally mounted in the hole in said. bushing whereby its end may be adjusted toward and from the other conductor and retained in adjusted position to form a variable spark gap between said Wire and said conductor to vary the duration of light flashes p-roduced by said glow device.

3. In an instument for use in synchronizing two parts by means of eects obtained by electric light flashes, the combination of a metallic body tube, a hollow lining member of insulated material extending substantially from end to end of and within said body tube, a block of insulating material in said body tube and fixed to said lining member, a gas lled glow device mounted uponsaid body tube at one end of said block, a pair of conductors mounted in and extending through said block and having electrical contact at one end thereof with the terminals of said glow device, a bushing of insulating material secured at the other end of said body tube and engaging the adjacent end of said lining member,

a pair of electric wires, one of which extends i through said bushing and contacts with one of said conductors, and the other electric wire being extended through a sleeve of somewhat yielding material which extends through and frictionally RICHARD MAXWELL EATON. 

